ha ha ... it's not a pure 2D painting program in fact ... so yes perhaps hard to recognize : it's 3D coat
Yes 3D coat is scultping,retopo,uv tool, but also great painting tool. It has a very usefull feature that is Texture Tile making. You choose the resolution and you can paint on the maps you want : diffuse, normal, specular. You have : -layers -brushes -masks -bézier curves, reactangles, paths -several lighten/Darken tools -simple blurr (just press Shift when painting)
I forgot , you can indeed paint in 3D on your 3D model and any of the maps (diffuse/Norm/spec).